Changes:
Names are renamed to task_context_switch_rates.
Patch makes available to the user the following
task and process performance statistics:
* Involuntary Context Switches (task_struct->nivcsw)
* Voluntary Context Switches (task_struct->nvcsw)
Statistics information is available from:
1. taskstats interface (Documentation/accounting/)
2. /proc/PID/status (task only).
This data is useful for detecting hyperactivity
patterns between processes.
Signed-off-by: Maxim Uvarov <[email protected]>
---
Documentation/accounting/getdelays.c | 19 +++++++++++++++++--
Documentation/accounting/taskstats-struct.txt | 6 ++++++
fs/proc/array.c | 8 ++++++++
include/linux/taskstats.h | 5 ++++-
kernel/taskstats.c | 4 ++++
5 files changed, 39 insertions(+), 3 deletions(-)
diff --git a/Documentation/accounting/getdelays.c b/Documentation/accounting/getdelays.c
index e9126e7..fcfe796 100644
--- a/Documentation/accounting/getdelays.c
+++ b/Documentation/accounting/getdelays.c
@@ -49,6 +49,7 @@ char name[100];
int dbg;
int print_delays;
int print_io_accounting;
+int print_task_context_switch_rates;
__u64 stime, utime;
#define PRINTF(fmt, arg...) { \
@@ -187,7 +188,7 @@ void print_delayacct(struct taskstats *t)
"IO %15s%15s\n"
" %15llu%15llu\n"
"MEM %15s%15s\n"
- " %15llu%15llu\n\n",
+ " %15llu%15llu\n"
"count", "real total", "virtual total", "delay total",
t->cpu_count, t->cpu_run_real_total, t->cpu_run_virtual_total,
t->cpu_delay_total,
@@ -196,6 +197,14 @@ void print_delayacct(struct taskstats *t)
"count", "delay total", t->swapin_count, t->swapin_delay_total);
}
+void task_context_switch_rates(struct taskstats *t)
+{
+ printf("\n\nTask %15s%15s\n"
+ " %15lu%15lu\n",
+ "voluntary", "nonvoluntary",
+ t->nvcsw, t->nivcsw);
+}
+
void print_ioacct(struct taskstats *t)
{
printf("%s: read=%llu, write=%llu, cancelled_write=%llu\n",
@@ -227,7 +236,7 @@ int main(int argc, char *argv[])
struct msgtemplate msg;
while (1) {
- c = getopt(argc, argv, "diw:r:m:t:p:v:l");
+ c = getopt(argc, argv, "qdiw:r:m:t:p:v:l");
if (c < 0)
break;
@@ -240,6 +249,10 @@ int main(int argc, char *argv[])
printf("printing IO accounting\n");
print_io_accounting = 1;
break;
+ case 'q':
+ printf("printing task/process context switch rates\n");
+ print_task_context_switch_rates = 1;
+ break;
case 'w':
strncpy(logfile, optarg, MAX_FILENAME);
printf("write to file %s\n", logfile);
@@ -381,6 +394,8 @@ int main(int argc, char *argv[])
print_delayacct((struct taskstats *) NLA_DATA(na));
if (print_io_accounting)
print_ioacct((struct taskstats *) NLA_DATA(na));
+ if (print_task_context_switch_rates)
+ task_context_switch_rates((struct taskstats *) NLA_DATA(na));
if (fd) {
if (write(fd, NLA_DATA(na), na->nla_len) < 0) {
err(1,"write error\n");
diff --git a/Documentation/accounting/taskstats-struct.txt b/Documentation/accounting/taskstats-struct.txt
index 661c797..dc2a7a1 100644
--- a/Documentation/accounting/taskstats-struct.txt
+++ b/Documentation/accounting/taskstats-struct.txt
@@ -22,6 +22,8 @@ There are three different groups of fields in the struct taskstats:
/* Extended accounting fields end */
Their values are collected if CONFIG_TASK_XACCT is set.
+4) Per-task and per-thread context switch rates statistics
+
Future extension should add fields to the end of the taskstats struct, and
should not change the relative position of each field within the struct.
@@ -158,4 +160,8 @@ struct taskstats {
/* Extended accounting fields end */
+4) Per-task and per-thread statistics
+ __u64 nvcsw; /* Context voluntary switch counter */
+ __u64 nivcsw; /* Context involuntary switch counter */
+
}
diff --git a/fs/proc/array.c b/fs/proc/array.c
index 70e4fab..cf406e8 100644
--- a/fs/proc/array.c
+++ b/fs/proc/array.c
@@ -290,6 +290,13 @@ static inline char *task_cap(struct task_struct *p, char *buffer)
cap_t(p->cap_permitted),
cap_t(p->cap_effective));
}
+static inline char *task_context_switch_rates(struct task_struct *p, char *buffer)
+{
+ return buffer + sprintf(buffer, "voluntary_ctxt_switches:\t%lu\n"
+ "nonvoluntary_ctxt_switches:\t%lu\n",
+ p->nvcsw,
+ p->nivcsw);
+}
int proc_pid_status(struct task_struct *task, char * buffer)
{
@@ -309,6 +316,7 @@ int proc_pid_status(struct task_struct *task, char * buffer)
#if defined(CONFIG_S390)
buffer = task_show_regs(task, buffer);
#endif
+ buffer = task_context_switch_rates(task, buffer);
return buffer - orig;
}
diff --git a/include/linux/taskstats.h b/include/linux/taskstats.h
index 3fced47..6927f81 100644
--- a/include/linux/taskstats.h
+++ b/include/linux/taskstats.h
@@ -31,7 +31,7 @@
*/
-#define TASKSTATS_VERSION 3
+#define TASKSTATS_VERSION 4
#define TS_COMM_LEN 32 /* should be >= TASK_COMM_LEN
* in linux/sched.h */
@@ -146,6 +146,9 @@ struct taskstats {
__u64 read_bytes; /* bytes of read I/O */
__u64 write_bytes; /* bytes of write I/O */
__u64 cancelled_write_bytes; /* bytes of cancelled write I/O */
+
+ __u64 nvcsw; /* voluntary_ctxt_switches */
+ __u64 nivcsw; /* nonvoluntary_ctxt_switches */
};
diff --git a/kernel/taskstats.c b/kernel/taskstats.c
index 4c3476f..e5bc666 100644
--- a/kernel/taskstats.c
+++ b/kernel/taskstats.c
@@ -196,6 +196,8 @@ static int fill_pid(pid_t pid, struct task_struct *tsk,
/* fill in basic acct fields */
stats->version = TASKSTATS_VERSION;
+ stats->nvcsw = tsk->nvcsw;
+ stats->nivcsw = tsk->nivcsw;
bacct_add_tsk(stats, tsk);
/* fill in extended acct fields */
@@ -242,6 +244,8 @@ static int fill_tgid(pid_t tgid, struct task_struct *first,
*/
delayacct_add_tsk(stats, tsk);
+ stats->nvcsw += tsk->nvcsw;
+ stats->nivcsw += tsk->nivcsw;
} while_each_thread(first, tsk);
unlock_task_sighand(first, &flags);
-
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